Growth and Low Temperature Transport Measurements of Pure and Doped Bismuth Selenide

Superconductivity;Topological insulator;transport;nanostructure;growth;low temperature;spin orbit;nanodevice;Physics

Mlack, Jerome ThomasMarkovic, Nina ;

Johns Hopkins University

关键词: Superconductivity;    Topological insulator;    transport;    nanostructure;    growth;    low temperature;    spin orbit;    nanodevice;    Physics;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/39395/MLACK-DISSERTATION-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Strong spin orbit materials have become especially interesting due to their potential for applications in spintronics, novel transistors, and the search for Majorana fermions. In order to fully take advantage of these materials they must be thoroughly studied. This work focuses on the material Bi2Se3, which is a strong spin orbit material and a topological insulator. I describe a synthesis technique and low-temperature transport measurements of nanostructures of Bi2Se3, that when annealed with palladium show evidence of superconductivity. The growth method is a catalyst-free atmospheric pressure vapor-solid growth. The growth method yields a variety of nanostructures, and materials analysis shows ordered structures of bismuth selenide in all cases. Low-temperature measurements of as-grown nanostructures indicate tunable carrier density in all samples. By doping the nanostructures with palladium via annealing, the transport properties of the samples can be altered to exhibit superconductivity. Thin films of palladium are deposited on prefabricated Bi2Se3 nanodevices and annealed at temperatures in excess of 100 degrees Celsius. We find that Bi2Se3 absorbs Pd under these conditions and that the absorption of Pd results in evidence of superconductivity, as shown by transport measurements measurements below 1K.